Tutorial 1 – Simple and Compound interest
After working through this study unit you should be able to
• Explain the difference between simple interest and compound interest
• Calculate simple interest
• Use the simple interest formula to determine the principal, rate and time
1.1 Simple & Compound Interest Formulae
1 FV = PV (1 + i x t)
FV = future value
PV = present value
1 = constant
i = interest rate
t = time (In years)
2 FV = PV (1 + i x t)
1.2 Compounding
Monthly 12
Annual 1
Quarterly 4
Bi-annual/ half yearly/ semi-annual 2
1.3 Simple interest
1. If you invest R35 000 for 8 years with simple interest being calculated at 9.5% per annum, what is the amount at the end of the period?
FV = PV (1 + i x t)
= R35 000(1 + 9.5% x 8)
= R61 600
Tip: this is a simple interest question because of the wording of the questions. The question is looking at the amount at the end of the period. This is known as the future value.
2. If you borrowed R200 000 for 82 months at 11.05% simple interest per annum, how much will you repay at the end of the period?
FV = PV (1 + i x t)
= R200 000(1 + 11.05% x 82/12)
Tip: this is a simple interest question because of the wording of the questions. The question is looking at the amount at the end of the period. This is known as the future value.
Tip: when the time is in months, convert then into years. This is done by dividing the months given by 12.
3. Calculate the simple interest on R70 000 borrowed for 36 months at 11.8% per annum.
I = PV x i x t
= R70 000 x 11.8% x 36/12
= R24 780
4 What is the principal that must be invested for 2 years at 4 1⁄2% to earn R25 000 simple interest?
PV = I/ (i x t)
= R25 000/ (0.045 x 2)
= R277 777.78
1.4 Simple interest
1. If an investor invests R149 000 for 5 years at an interest rate of 3.5% per annum, what will the value of his investment be at the end of the 5 years if interest is calculated as follows:
Interest compounded half-yearly
FV = PV (1 + i/m) ^mn
= R149 000(1 + 3.5%/2) ^ 20
= R210 801.95
2. An investment will be worth R155 000 if invested for 72 months at a rate of 5.75% per annum, compounded quarterly. What is the present value of the investment?
PV = FV/ (1 = i)^mn
= R155 000/ (1+ 5.75%/4) ^ 24
= R110 044.11
Tip: when time is given in months convert it to years by dividing the given months by 12. m refers
to how many times one is getting interest per year. n refers to the number of years. Note the following value of m:
Quarterly = 4
Monthly = 12
Annually = 1
Half yearly = 2
🔥 EXAM TIP
Simple interest and compound interest is one important of the important areas in your BUSL exams for Institute of Certified Bookkeepers.
📘 Mini Multiple-Choice Check
1. Certain amounts will be included in a person’s gross income despite the fact that these amounts are of a capital nature or from a non-South African source. The following are examples of special inclusions, and included in gross income:
A. Donations
B. Inheritances
C. Recoupments
D. Gifts
Correct Answer: C – Recoupments
2. From various court cases, one indication that expenditure is of a revenue nature, and is not a tax-deductible expense is:
A. The expense is recurrent
B. The expense is once off expenditure from which future income will flow
C. The expense adds to a taxpayer’s income-earning structure
D. The expense creates a lasting benefit for the taxpayer
Correct Answer: A – The expense is recurrent
3. Which of the following expenses may a salaried employee deduct from his gross income?
A. The cost of travelling between work and home
B. Retirement annuity contributions allowed in terms of S11F
C. Childcare costs incurred so he is able to work
D. Home office expenditure
Correct Answer: B – Retirement annuity contributions allowed in terms of S11F
4. The following provided by an employer to an employee will result in a taxable benefit in the employees’ hands:
A. A meal provided when an employee is required to entertain a client on behalf of the employee
B. A meal provided during working hours
C. A meal provided from restaurant vouchers awarded for good service by the employee
D. A meal provided in a canteen that is operated on an employer’s behalf and used mainly by employees
Correct Answer: C – A meal provided from restaurant vouchers awarded for good service by the employee
5. Adam Smith who wrote the ground breaking book in 1776 called the ‘Wealth of Nations’ stated that one of the basic principles of tax is that the amount of tax which each individual is bound to pay should be uncertain and arbitrary
A. True
B. False
Correct Answer: False